Composition for stripping photoresist and method for manufacturing thin transistor array panel using the same

ABSTRACT

The present invention provides a photoresist stripper including about 5 wt % to about 20 wt % alcohol amine, about 40 wt % to about 70 wt % glycol ether, about 20 wt % to about 40 wt % N-methyl pyrrolidone, and about 0.2 wt % to about 6 wt % chelating agent.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.11/217,400, filed Sep. 2, 2005 now U.S. Pat. No. 7,294,518 which claimspriority to Korean Patent Application No. 10-2004-0077501, filed Sep.24, 2004, the disclosures of which are incorporated by reference hereinin their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present description relates to a stripper for photoresist and amethod for manufacturing a thin film transistor (TFT) array panel usingthe same.

2. Description of the Related Art

Liquid crystal displays (LCDs) are some of the most widely used flatpanel displays. An LCD includes a liquid crystal (LC) layer that isinterposed between two panels that are provided with field-generatingelectrodes. The LCD displays images by applying voltages to thefield-generating electrodes to generate an electric field in the LClayer which orients the LC molecules in the LC layer to adjust thepolarization of incident light.

An LCD that includes two panels that are provided with field-generatingelectrodes, wherein one panel has a plurality of pixel electrodes thatare arranged in a matrix and the other has a common electrode thatcovers the entire surface of the panel, dominates the LCD market.

The LCD displays images by applying a different voltage to each pixelelectrode. For this reason, TFTs that have three terminals to switchvoltages that are applied to the pixel electrodes are connected to thepixel electrodes. In addition, gate lines that transmit signals forcontrolling the thin film transistors and data lines that transmitvoltages that are applied to the pixel electrodes are formed on a thinfilm transistor array panel.

A TFT is a switching element that transmits image signals from the dataline to the pixel electrode in response to scanning signals from thegate line. The TFTs are applied to active matrix organic light emittingdisplays to control light emitting elements.

Considering the trend of increasing LCD sizes, a material that has lowresistivity is required since the lengths of the gate lines and datalines also increase along with the LCD size.

Aluminum is a metal that has a sufficiently low resistivity and may beused in an LCD. However, since aluminum has weak chemical resistance, itis vulnerable to an etchant and a photoresist stripper that are sued forpatterning thin film patterns. Accordingly, signal lines made ofaluminum often have a defective profile such as an undercut and anoverhang.

SUMMARY OF THE INVENTION

The present invention provides a photoresist stripper that dissolves andstrips photoresist coatings and does not erode metal lines under thephotoresist.

The present invention also provides a method for manufacturing a TFTarray panel using the photoresist stripper.

Additional features of the invention will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention.

The present invention discloses a photoresist stripper comprising about5 wt % to about 20 wt % of an alcohol amine, about 40 wt % to about 70wt % of a glycol ether, about 20 wt % to 40 wt % of N-methylpyrrolidone, and about 0.2 wt % to about 6 wt % of a chelating agent.

The present invention also discloses a photoresist stripper comprisingabout 5 wt % to about 20 wt % of N-monoethanol amine, about 40 wt % toabout 70 wt % of butyl diglycol, about 20 wt % to about 40 wt % ofN-methyl pyrrolidone, about 0.1 wt % to about 3 wt % of methyl gallate,and about 0.1 wt % to about 3 wt % of hydroxyl ethyl piperazinepiperasane.

The present invention also discloses a method for manufacturing a TFTarray panel using the photoresist stripper comprising forming a gateline having a gate electrode on an insulating substrate, depositing agate insulating layer, a semiconductor layer, and a ohmic contact layeron the gate line, patterning the semiconductor layer and the ohmiccontact layer, and forming a drain electrode and a data line having asource electrode on the gate insulating layer and the ohmic contactlayer, where the drain electrode faces the source electrode with a gaptherebetween. The method further comprises forming a passivation layerhaving a contact hole exposing the drain electrode, and forming a pixelelectrode connected to the drain electrode through the contact hole onthe passivation layer. At least one step of forming the gate line andforming the drain electrode and the data line includes stripping aphotoresist layer with a photoresist stripper comprising about 5 wt % toabout 20 wt % of an alcohol amine, about 40 wt % to about 70 wt % of aglycol ether, about 20 wt % to about 40 wt % of N-methyl pyrrolidone,and about 0.2 wt % to about 6 wt % of a chelating agent.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a layout view of a TFT array panel for an LCD according to anexemplary embodiment of the present invention.

FIG. 2 is a sectional view of the TFT array panel shown in FIG. 1 takenalong line II-II′.

FIG. 4, FIG. 4, FIG. 5, FIG. 6B, FIG. 7B, FIG. 8, FIG. 9, FIG. 10, FIG.11B, and FIG. 12B are sectional views that sequentially illustrate stepsof manufacturing a TFT array panel for an LCD according to the exemplaryembodiment of FIG. 1 and FIG. 2.

FIG. 6A, FIG. 7A, FIG. 11A, and FIG. 12A are layout views thatsequentially illustrate steps of manufacturing a TFT array panel for anLCD according to the exemplary embodiment of FIG. 1 and FIG. 2.

FIG. 13 is a layout view of a TFT array panel for an LCD according toanother exemplary embodiment of the present invention.

FIG. 14 is a sectional view of the TFT array panel shown in FIG. 13taken along line XIV-XIV′.

FIG. 15, FIG. 16, FIG. 17, FIG. 18B, FIG. 19, FIG. 20, FIG. 21B, andFIG. 22B are sectional views that sequentially illustrate steps ofmanufacturing a TFT array panel for an LCD according to the exemplaryembodiment of FIG. 13 and FIG. 14.

FIG. 18A, FIG. 21A, and FIG. 22A are layout views that sequentiallyillustrate steps of manufacturing a TFT array panel for an LCD accordingto the exemplary embodiment of FIG. 13 and FIG. 14.

FIG. 23A is a sectional photograph showing eroded features of analuminum layer using a conventional photoresist stripper.

FIG. 23B is a sectional photograph showing eroded features of analuminum layer using a photoresist stripper according to an exemplaryembodiment of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The photoresist stripper of the present invention has good strippingabilities and may not corrode metal. In addition, the photoresiststripper prevents a defective profile of signal lines such as undercutand overhang.

The present invention provides a photoresist stripper comprising about 5wt % to about 20 wt % of an alcohol amine, about 40 wt % to about 70 wt% of a glycol ether, about 20 wt % to about 40 wt % of N-methylpyrrolidone, and about 0.2 wt % to about 6 wt % of a chelating agent.

The alcohol amine may include, but is not limited to monoisopropanolamine (CH₃CH(OH)CH₂NH₂) or N-monoethanol amine (HO(CH₂)₂NH₂). Thealcohol amine is preferably N-monoethanol amine (HO(CH₂)₂NH₂). Thephotoresist stripper may comprise about 5 wt % to about 20 wt % of analcohol amine. When the photoresist stripper comprises less than 5 wt %of alcohol amine, the stripping ability of the photoresist stripper isweakened due to evaporation of the alcohol amine as the strippingprocess progresses. Accordingly, particles of the photoresist remain onthe patterned film. When the photoresist stripper comprises more than 20wt % alcohol amine, the photoresist stripper has too high an angle ofcontact with the photoresist. Accordingly the photoresist stripper doesnot absorb into the photoresist well.

Glycol ether is added to the photoresist stripper to dissolve thephotoresist and to control surface tension. The glycol ether mayinclude, but is not limited to carbitol [C₂H₅O(CH₂CH₂O)₂H)], methyldiglycol [CH₃O(CH₂CH₂O)₂H], and butyl diglycol [C₄H₉)(CH₂CH₂O)₂H]. Theglycol ether is preferably butyl diglycol. The photoresist strippercomprises about 40 wt % to about 70 wt % of glycol ether. When thephotoresist stripper comprises less than 40 wt % glycol ether, thephotoresist stripper has too high an angle of contact with thephotoresist. Accordingly the photoresist stripper does not absorb intothe photoresist well. When the photoresist stripper comprises more than70 wt % glycol ether, the photoresist stripping ability of thephotoresist stripper is degraded.

N-methyl pyrrolidone [C₅H₉NO] is also added to the photoresist stripperto dissolve the photoresist along with glycol ether. Since N-methylpyrrolidone has a strong polarity, N-methyl pyrrolidone preserves thestripping ability of the photoresist stripper even after repeatedstripping. The photoresist stripper comprises about 20 wt % to about 40wt % of N-methyl pyrrolidone. When the photoresist stripper comprisesless than 20 wt % N-methyl pyrrolidone, its ability of dissolvingphotoresist is too weak. When the photoresist stripper comprises morethan 40 wt % N-methyl pyrrolidone, the photoresist stripper has toostrong a polarity which requires an additional amount of alcohol amine.

A chelating agent reduces galvanic corrosion of a metal such asaluminum, which has weak chemical resistance. When double metal layersof aluminum and molybdenum are soaked by a photoresist stripper,electrons migrate from the aluminum layer to the molybdenum layer tocorrode the aluminum layer by galvanic corrosion. When the photoresiststripper contains a chelating agent, the chelating agent reducesgalvanic corrosion to prevent the aluminum layer from being undercut.The photoresist stripper preferably contains one of methyl gallate,hydroxyl ethyl piperazine piperasane (HEP), and their mixture as achelating agent.

the photoresist stripper may comprise about 0.2 wt % to about 6 wt % ofa chelating agent. When the photoresist stripper comprises less than 0.2wt % of the chelating agent, the effect of restraining galvaniccorrosion is not shown. When the photoresist stripper comprises morethan 6 wt % of the chelating agent, metal layers may be adverselyaffected.

The present invention also provides a method for manufacturing a TFTarray panel using the mentioned photoresist stripper.

Henceforth, preferred embodiments of the present invention will bedescribed more fully with reference to the accompanying drawings, inwhich preferred embodiments of the invention are shown. The presentinvention may, however, be embodied in different forms and should not beconstrued as being limited to the embodiments set forth herein. Rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the invention to thoseskilled in the art.

In the drawings, the thickness of layers, films, and regions areexaggerated for clarity. Like numerals refer to like elementsthroughout. It will be understood that when an element such as a layer,film region, or substrate is referred to as being “on” another element,it can be directly on the other element or intervening elements may alsobe present.

Embodiment 1 and Embodiment 2

In Embodiment 1 and Embodiment 2, the tripping ability and the degree ofaluminum corrosion of the photoresist stripper of the present inventionwill be compared with a conventional photoresist stripper. Photoresiststrippers that comprise an alcohol amine, a solvent of an alcohol amine,and other elements are prepared according to Table 1.

In the present embodiment, N-monoethanol amine (N-MEA) is applied as analcohol amine that strips a photoresist. Butyl diglycol (BDG) andN-methyl pyrrolidone (NMP) are applied as solvents. Methyl gallate (MG)and hydroxyl ethyl piperazine piperasane (HEP) are applied as chelatingagents. The references are conventional photoresist strippers comprisingN-MEA, BDG, and NMP or N-MEA, dimethylsulfoxide (DMSO), and deionizedwater (DI).

TABLE 1 Unit: wt % Embodiment 1 Embodiment 2 Reference 1 Reference 2N-MEA 15 18 10 30 BDG 47 51 35 — NMP 35 25 55 — DMSO — — — 50 MG 1.5 3 —— HEP 1.5 3 — — DI — — — 20

Stripping ability and degree of aluminum corrosion of the photoresiststrippers according to Embodiment 1, Embodiment 2, Reference 1 andReference 2 were measured.

A. Test of Stripping Ability

Photoresist layers were spin-coated to a thickness of 2.0 μm of fourbare glass plates with a size of 10 cm×10 cm. At a temperature of about65° C., the photoresist strippers of Embodiment 1, Embodiment 2,Reference 1, and Reference 2 were respectively sprayed on the fourphotoresist layers for over 180 seconds and then cleaned with deionizedwater for 30 seconds. Next, the four glass plates were observed by thenaked eye and through a microscope.

It was found that the photoresist strippers of Embodiment 1 andEmbodiment 2 showed a high stripping ability and the photoresiststrippers of Reference 1 showed a somewhat degraded stripping abilitycompared to the photoresist strippers of Embodiment and Embodiment 2.The photoresist stripper of Reference 2 also showed a poor strippingability.

B. Test of Degree of Aluminum Corrosion

Double layered metal patterns including an aluminum layer and amolybdenum layer were formed on three bare glass plates with a size of10 cm×10 cm using photoresist layers. The photoresist strippers ofEmbodiment 1, Embodiment 2, Reference 1, and Reference 2 wererespectively sprayed on the photoresist layers for over 150 seconds,cleaned with deionized water for 30 seconds, and then dried.

As shown in FIG. 23B, the metal patterns applied with the photoresiststrippers of Embodiment 1 and Embodiment 2 had fine profiles withoutcorrosion of the lower layer of aluminum. However, as shown in FIG. 23Athe metal pattern applied with the photoresist strippers of Reference 1had a poor profile including a 1434 nm undercut of the lower layer ofaluminum.

Thus, the photoresist strippers of Embodiment 1 and Embodiment 2 of thepresent invention have superior stripping ability and are less corrosiveto aluminum than the conventional photoresist strippers.

Embodiment 3

A TFT array panel fabricated using a photoresist stripper of Embodiment1 and a photoresist stripper of Embodiment 2 and manufacturing methodsthereof will be described in detail with reference to the accompanyingdrawings.

FIG. 1 is a layout view of a TFT array panel for an LCD of an exemplaryembodiment of the present invention, and FIG. 2 is a sectional view ofthe TFT array panel shown in FIG. 1 taken along line II-II′.

A plurality of gate lines 121 for transmitting gate signals are formedon an insulating substrate 110. The gate lines 121 are mainly formed ina horizontal direction, and partial portions thereof become a pluralityof gate electrodes 124. Also, different partial portions thereof thatextend in a lower direction become a plurality of expansions 127.

The gate line 121 has lower layers 124 a and 127 a and upper layers 124b and 127 b. The lower layers 124 a and 127 a may comprise analuminum-containing metal such as pure aluminum or aluminum-neodymium(Al—Nd) but is not limited thereto. The upper layers 124 b and 127 b maycomprise, but are not limited to molybdenum.

The lateral sides of the upper layers 124 b and 127 b and lower layers124 a and 127 a are inclined relative to a surface of the substrate 110with an inclination angle ranging from about 30 degrees to about 80degrees.

A gate insulating layer 140 preferably comprising silicon nitride (SiNx)is formed on the gate lines 121.

A plurality of semiconductor stripes 151, preferably comprisinghydrogenated amorphous silicon (“a-Si”), are formed on the gateinsulating layer 140. Each semiconductor stripe 151 extendssubstantially in the longitudinal direction and curves periodically.Each semiconductor stripe 151 has a plurality of projections 154 thatbranch out toward the gate electrodes 124. The width of eachsemiconductor stripe 151 increases near the gate lines 121 such that thesemiconductor stripe 151 covers large areas of the gate lines 121.

A plurality of ohmic contact 163 and 165, preferably made of silicide orn+ hydrogenated a-Si heavily doped with an n-type impurity, are locatedin pairs on the projections 154 of semiconductor stripes 151.

The edge surfaces of the semiconductor stripes 151 and the ohmiccontacts 163 and 165 are tapered such that the inclination angles of theedge surfaces of the semiconductor stripes 151 and the ohmic contacts163 and 165 are preferably in a range of about 30 degrees to about 80degrees.

A plurality of data lines 171, a plurality of drain electrodes 175, anda plurality of storage capacitor conductors 177 are formed on the ohmiccontacts 163 and 165 and the gate insulating layer 140.

The data lines 171, which transmit data voltages, extend substantiallyin the longitudinal direction and intersect the gate lines 121 to definepixel areas that are arranged in a matrix. A plurality of branches ofeach data line 171 that project toward the drain electrodes 175 form aplurality of source electrodes 173. Each pair of the source electrodes173 and the drain electrodes 175 are separated from each other on thegate electrodes 124, and oppose each other. Each data line 171 has anend portion 179 for connection with another layer or external drivingcircuits.

The data line 171, the drain electrode 175, and the storage capacitorconductor 177 have first layers 171 a, 175 a, second layers 171 b, 175b, and 177 b, and third layers 171 c, 175 c, and 177 c, respectively.The first layers 171 a, 175 a, and 177 a and the third layers 171 c, 175c, and 177 c are respectively disposed at lower and upper sides of thesecond layers 171 b, 175 b, and 177 b. The first layers 171 a, 175 a,and 177 a and the third layers 171 c, 175 c, and 177 c comprise amolybdenum-containing metal. The second layers 171 b, 175 b, and 177 bcomprise an aluminum-containing metal.

Since the aluminum or aluminum alloy layer with low resistivity isdisposed between the two molybdenum-alloy layers, the data line 171 haslow resistivity and the aluminum or aluminum-alloy layer is preventedfrom contacting the semiconductor and pixel electrodes that may causepoor contact. Accordingly, degradation of TFTs caused by poor contact isefficiently prevented.

A gate electrode 124, a source electrode 173, and a drain electrode 175,along with a projection 154 of a semiconductor stripe 151 form a TFTwith a channel that is formed in the projection 154 that is disposedbetween the source electrode 173 and the drain electrode 175. Thestorage capacitor conductor 177 is overlapped with the expansion 127 ofthe gate line 121.

The data lines 171, the drain electrodes 175, and the storage capacitorconductor 177 have tapered edge surfaces such that the inclinationangles of the edge surfaces range from about 30 degrees to about 80degrees.

The ohmic contacts 164 and 165 are interposed between the semiconductorstripe 151 and the data line 171 and between the drain electrode 175 andthe projection 154 of the semiconductor stripe 151 to reduce contactresistance therebetween. The semiconductor stripe 151 is partiallyexposed at the place between the source electrode 173 and the drainelectrode 175 and at the other places that are not covered with the dataline 171 and the drain electrode 175. Most of the semiconductor stripe151 is narrower than the data line 171, but the width of thesemiconductor stripe 151 broaches near a place where the semiconductorstripe 151 and the gate line 121 intersect to prevent disconnection ofthe data line 171.

A passivation layer 180 is provided on the data line 171, the drainelectrode 175, the storage capacitor conductor 177, and the exposedregion of the semiconductor stripe 151. The passivation layer 180comprises an organic material having substantial planarizationproperties and photosensitivity or an insulating material with a lowdielectric constant such as a-Si:C:O, a Si:O:F, for example. Thispassivation layer 180 is formed by plasma enhanced vapor deposition(PECVD). To prevent the organic material of the passivation layer 180from contacting the semiconductor stripes 151 that are exposed betweenthe data line 171 and the drain electrode 175, the passivation layer 180may be structured so that an insulating layer comprising SiNx or SiO₂ isadditionally formed under the organic material layer.

In the passivation layer 180, a plurality of contact holes 185, 187, and182 are formed to expose the drain electrode 175, the storage capacitorconductor 177, and an end portion of the data line 171, respectively.

A plurality of pixel electrodes 190 and a plurality of contactassistants 82, which are made of indium zinc oxide (IZO) or indium tinoxide (ITO), are formed on the passivation layer 180.

Since the pixel electrode 190 is coupled with the drain electrode 175and the storage capacitor conductor 177 through the contact holes 185and 187, respectively, the pixel electrode 190 receives the data voltagefrom the drain electrode 175 and transmits it to the storage capacitorconductor 177.

The pixel electrode 190, to which the data voltage is applied, generatesan electric field with a common electrode (not illustrated) of theopposite panel (not illustrated) to which a common voltage is applied,so that a liquid crystal molecules in the liquid crystal layer may bealigned.

Also, as mentioned above, the pixel electrode 190 and the commonelectrode form a capacitor to store and preserve the received voltageafter the TFT is turned off. This capacitor is referred to as a “liquidcrystal capacitor.” To enhance the voltage storage ability, anothercapacitor is coupled in parallel with the liquid crystal capacitor andwill be referred to as a “storage capacitor.” the storage capacitor isformed at an overlapping portion of the pixel electrode 190 and theadjacent gate line 121, which will be referred to as a “previous gateline.” The expansion 127 of the gate line 121 is provided to ensure thelargest possible overlap and to thus increase the storage capacity ofthe storage capacitor. The storage capacitor conductor 177 is coupledwith the pixel electrode 190 and is overlapped with the expansion 127,and is provided at the bottom of the passivation layer 180 so that thepixel electrode 190 becomes close to the previous gate line 121.

The pixel electrode 190 may be overlapped with the adjacent gate line121 and the adjacent data line 171 to enhance the aperture ratio.

The contact assistant 82 supplements adhesion between the end portion ofthe data line 171 and the exterior devices, such as a driving integratedcircuit, and protects them. Applying the contact assistant 82 isoptional since it is not an essential element.

A method for manufacturing a TFT array panel will be now described indetail with reference to FIG. 3, FIG. 4, FIG. 5, FIG. 6A, FIG. 6B, FIG.7A, FIG. 7B, FIG. 8, FIG. 9, FIG. 10, FIG. 11A, FIG. 11B, FIG. 12A andFIG. 12B as well as FIG. 1 and FIG. 2.

As shown in FIG. 3, a first metal layer 120 a and a second metal layer120 b are sequentially deposited on an insulating substrate 110. Thefirst and second metal layers 120 a and 120 b may be deposited byco-sputtering, which is performed as follows.

Two targets are installed in the same sputtering chamber for theco-sputtering. One target comprises aluminum or aluminum-neodymium, andthe other target comprises a molybdenum alloy.

At first, power is applied to the aluminum (or aluminum-neodymium)target while no power is applied to the molybdenum-alloy target todeposit a lower layer of aluminum (or aluminum-neodymium). The thicknessof the lower layer is preferably about 2,500 Å.

Next, power is applied to the molybdenum-alloy target and not to thealuminum (or aluminum-neodymium) target to deposit an upper layer.

Next, as shown in FIG. 4, a photoresist layer 40 is coated on the secondmetal layer 120 b and is exposed to light through a photomask 50. Then,the photoresist layer 40 is developed.

Next, as shown in FIG. 5, portions of the second metal layer 120 b andthe first metal layer 120 a, which are not covered by the photoresistpattern 40 a, are etched with an etchant. The etchant may preferablycomprise phosphoric acid, nitric acid, acetic acid, and deionized waterin predetermined proportions.

Then, the photoresist pattern 40 a is stripped by the photoresiststripper of Embodiment 1 of the present invention. The photoresiststripper is sprayed on the photoresist pattern 40 a and left for about60 seconds to about 300 seconds at a temperature of about 50° C. toabout 80° C.

In the present embodiment, the photoresist stripper comprises 15 wt %N-MEA 47 wt % of BDG, 35 wt % of NMP, 1.5 wt % MG, and 1.5 wt % of HEP.However, the proportions of the components of the photoresist strippermay be varied in ranges of about 5 wt % to about 20 wt % of an alcoholamine, about 40 wt % to about 70 wt % of a glycol ether, about 20 wt %to about 40 wt % of N-methyl pyrrolidone, and about 0.2 wt % to about 6wt % of a chelating agent.

In the present embodiment, the photoresist stripper comprises N-MEA asthe alcohol amine, BDG as the glycol ether, and MG and HEP as thechelating agents. However, these components are only examples andvarious other components may be used. For example monoisopropanol amine(CH₃CH(OH)CH₂NH₂) may be used as the alcohol amine and carbitol[C₂H₂O(CH₂CH₂O)₂H)] or methyl diglycol [CH₂O(CH₂CH₂O₂H] may be used asthe glycol ether.

Through the above-described processes as shown in FIG. 6A and FIG. 6B, aplurality of gate lines 121 having a plurality of gate electrodes 124and expansions 127 are formed.

Referring to FIG. 7A and FIG. 7B, after sequential deposition of a gateinsulating layer 140, an intrinsic a-Si layer, and an extrinsic a-Silayer, the extrinsic a-Si layer and the intrinsic a-Si layer arephoto-etched to form a plurality of extrinsic semiconductor stripes (notshown) and a plurality of intrinsic semiconductor stripes 151respectively, having projections 164 and 154. The gate insulating layer140 preferably comprises silicon nitride with a thickness of about 2,000Å to about 5,000 Å, and the deposition temperature is preferably in arange of about 250° C. and about 500° C.

Next, as shown in FIG. 8, a first layer 170 a of molybdenum-alloy, asecond layer 170 b of aluminum (or aluminum-alloy), and a third layer170 c of molybdenum-alloy are sequentially deposited on the extrinsicsemiconductor stripes and the gate insulating layer 140. The thicknessof the three layer 170 a, 170 b and 170 c is preferably about 3,000 Å.The sputtering temperature is preferably about 150° C.

Next, as shown in FIG. 9, a photoresist layer 41 is spin-coated on thethird layer 170 c and is exposed to light through a photo-mask 51 anddeveloped the photoresist layer 41. By exposing and developing, aplurality of photoresist patterns 41 a are formed as shown in FIG. 10.

Next, as shown in FIGS. 9 and 10, portions of the third to first layers170, which are not covered by the photoresist pattern 41 a, are etchedwith an etchant. The etchant preferably comprises phosphoric acid,nitric acid, acetic acid, and deionized water in predeterminedproportions.

Then, the photoresist pattern 41 a is stripped by the photoresiststripper as in Embodiment 1 and earlier in this third embodiment whenphotoresist pattern 40 a was stripped. The photoresist stripper issprayed on the photoresist pattern 41 a and left for about 60 seconds toabout 300 seconds at a temperature of about 50° C. to about 80° C.

Through the above-described processes as shown in FIG. 11A and FIG. 11B,a plurality of data lines 171 having a plurality of source electrodes173 and end portions 179, a plurality of drain electrodes 175, andstorage capacitor conductors 177 are formed.

Next, portions of the projections 164 of the extrinsic semiconductorstripes 161, which are not covered with the data lines 171 and the drainelectrodes 175, are removed by etching to complete a plurality of ohmiccontacts 163 and 165 and to expose portions of the intrinsicsemiconductor stripes 151. Oxygen plasma treatment may follow thereafterin order to stabilize the exposed surfaces of the semiconductor stripes151.

Referring to FIG. 12A and FIG. 12B, a passivation layer 180 is depositedand dry etched along with the gate insulating layer 140 to form aplurality of contact holes 185, 187, and 182. The gate insulating layer140 and the passivation layer 180 are preferably etched under an etchcondition having substantially the same etch ratio.

When the passivation layer comprises a photosensitive material, thecontact holes may be formed by photolithography.

Finally, as shown in FIG. 1 and FIG. 2, a plurality of pixel electrodes190 and a plurality of contact assistants 82 are formed by sputteringand photo-etching an IZO layer or an ITO layer.

The present embodiment illustrates gate lines 121 and data lines 171that both have a molybdenum-containing layer and an aluminum-containinglayer. However, it is possible that only one of the gate lines 121 anddata lines 171 have multiple layers.

Embodiment 4

The data lines and the semiconductors are formed by differentphotoetching processes using different photomasks in the firstembodiment. However, the data lines and the semiconductors may be formedsimultaneously by a photoetching process using the same photomask toreduce production costs. Such an embodiment will be described in detailwith reference to the drawings.

FIG. 13 is a layout view of a TFT array panel for an LCD according toanother embodiment of the present invention, and FIG. 14 is a sectionalview of the TFT array panel shown in FIG. 13 taken along line XIV-XIV′.

As seen in FIG. 13 and FIG. 14, the layer structure of the presentembodiment is very similar to that of the TFT array panel shown in FIG.1 and FIG. 2.

That is, gate lines 121 having gate electrodes 124 are formed on aninsulating substrate 110. A gate insulating layer 140, semiconductorstripes 151 having protrusions 154, and ohmic contacts 163 and 165 aresequentially formed on the gate lines 121. A plurality of data lines 171having source electrodes 173 and a plurality of drain electrodes 175 areformed on the ohmic contacts 163 and 165 and the gate insulating layer140. The data lines 171 and the drain electrodes 175 have three metallayers including a first metal layer 171 a and 175 a comprising amolybdenum-containing metal, a second metal layer 171 b and 175 bcomprising an aluminum-containing metal and a third metal layer 171 cand 175 c comprising a molybdenum-containing metal. A passivation layer180 is formed on the data lines 171 and the source electrodes 173. Thepassivation layer 180 has a plurality of contact holes 182 and 185. Aplurality of pixel electrodes 190 and a plurality of contact assistants82 are formed on the passivation layer 180.

However, the TFT array panel according to the presents embodimentincludes a plurality of storage electrode lines 131 that are separatedfrom the gate lines 121 and overlap the drain electrode 175 to formstorage capacitors. The storage electrode lines 131 substitute for theexpansion 127 of the TFT array panel shown in FIG. 1 and FIG. 2.

The storage capacitors are formed by overlapping the pixel electrodes190 with the storage lines 131. The storage electrode lines 131 aresupplied with a predetermined voltage such as the common voltage. Thestorage electrode lines 131 may be omitted if the storage capacitancegenerated by the overlapping of the gate lines 121 and the pixelelectrodes 190 is sufficient. The storage electrode lines 131 may beformed along a boundary of the pixels to enhance the aperture ratio.

The data lines 171 and the drain electrodes 175 have substantially thesame planar pattern as the ohmic contacts 163 and 165. The semiconductorstripes 151 have substantially the same planar pattern with the ohmiccontacts 163 and 165 besides the protrusions 154. The semiconductorstripes 151 have exposed portions that are not covered by the sourceelectrodes 173 and the drain electrodes 175 and are disposedtherebetween.

A method for manufacturing the TFT array panel illustrated in FIG. 13and FIG. 14 will be now described in detail with reference to FIG. 15,FIG. 16, FIG. 17, FIG. 18A, FIG. 19, FIG. 20, FIG. 21A, FIG. 21B, FIG.22, and FIG. 22B as well as FIG. 13 and FIG. 14.

As shown in FIG. 15, a first metal layer 120 a and a second metal layer120 b are sequentially deposited on an insulating substrate 110 bysputtering. The first metal layer 120 a comprises aluminum or analuminum alloy. The second metal layer 120 b comprises molybdenum or amolybdenum alloy.

Next as shown in FIG. 16, a photoresist layer 42 is spin-coated on thesecond metal layer 120 b and is exposed to light through a photomask 52.Then, the photoresist layer 40 is developed.

Next, as shown in FIG. 17, portions of the second metal layer 120 b andthe first metal layer 120 a, which are not covered by the photoresistpattern 42 a, are etched with an etchant. The etchant may preferablycomprise phosphoric acid, nitric acid, acetic acid, and deionized waterin predetermined proportions.

Then, the photoresist pattern 42 a is stripped by the photoresiststripper of Embodiment 2 of the present invention. The photoresiststripper is sprayed on the photoresist pattern 42 a for about 60 secondsto about 300 seconds at a temperature of about 50° C. to about 80° C.

In the present embodiment, the photoresist stripper comprises about 18wt % of N-MEA, about 51 wt % of BDG, about 25 wt % of NMP, about 3.0 wt% of MG, and about 3.0 wt % of HEP. However, the proportions of thecomponents of the photoresist stripper may be varied in ranges of about5 wt % to about 20 wt % of the alcohol amine about 40 wt % to about 70wt % of the glycol ether, about 20 wt % to about 40 wt % of N-methylpyrrolidone and about 0.2 wt % to about 6 wt % of the chelating agent.

In the present embodiment the photoresist stripper comprises N-MEA asthe alcohol amine, BDG as the glycol ether, and MG and HEP as thechelating agents. However, those materials are only examples and variousother materials may be used. For example, monoisopropanol amine(CH₃CH(OH)CH₂NH₂) may be used as the alcohol may be used as the glycolether.

Through the above-described processes, as shown in FIG. 18A and FIG.18B, a plurality of gate lines 121 having a plurality of gate electrodes124 and a plurality of storage electrode lines 131 are formed.

Referring to FIG. 19, a gate insulating layer 140 comprising SiNx, anintrinsic semiconductor layer 150, and an extrinsic semiconductor layer160 are sequentially deposited. The intrinsic semiconductor layer 150preferably comprises hydrogenated a-Si, and the extrinsic semiconductorlayer 160 preferably comprises silicide or n+ hydrogenated a-Si heavilydoped with an n-type impurity.

Next, a first layer 170 a of a molybdenum-containing metal, a secondlayer 170 b of an aluminum-containing metal, and a third layer 170 c ofa molybdenum-containing metal are sequentially deposited on theextrinsic semiconductor layer 160.

A photoresist film is coated on the third layer 170 c. The photoresistfilm is exposed to light through a photomask (not shown), and developedsuch that the developed photoresist has a position-dependent thicknessas shown in FIG. 19. The developed photoresist includes a plurality offirst to third portions. The first portions 54 are located on channelareas B and the second portions 52 are located on the data line areas A.No reference numeral is assigned to the third portions that are locatedon the remaining areas C since they have substantially zero thickness.Here, the thickness ratio of the first portions 54 to the secondportions 52 is adjusted depending upon the process conditions in thesubsequent process steps. It is preferable that the thickness of thefirst portions 54 is equal to or less than half the thickness of thesecond portions 52.

The position-dependent thickness of the photoresist may be achieved byseveral techniques, for example, by providing translucent areas on thephotomask as well as transparent areas and light blocking opaque areas.The translucent areas may have a slit pattern a lattice pattern, or athin film(s) with intermediate transmittance or intermediate thickness,but are not limited thereto. When using a slit pattern, it is preferablethat the width of the slits or the distance between the slits is lessthan the resolution of a light exposer that is used for thephotolithography.

Another example is to use a reflowable photoresist. If a photoresistpattern made of a reflowable material is formed by using a normalexposure mask with only transparent areas and opaque areas, it issubject to a reflow process to flow onto areas without the photoresist,thereby forming thin portions.

As shown in FIG. 20, the photoresist film 52 and 54 and the underlyinglayers are then etched such that the data lines 171, drain electrodes175, and the underlying layers are left on the data areas A, only theintrinsic semiconductor layer is left on the channel areas B, and thegate is exposed on the remaining areas C.

Then, the photoresist patterns 52 and 54 are stripped by the photoresiststripper of Embodiment 2 and earlier in this fourth embodiment whenphotoresist pattern 42 a was stripped. The photoresist stripper asdescribed earlier is sprayed on the photoresist pattern 52 and 54 andleft for about 60 seconds to about 300 seconds at a temperature of about50° C. to about 80° C.

Through the above-described processes, as shown in FIG. 21A and FIG.21B, a plurality of data lines 171 having source electrodes 173, drainelectrodes 175, ohmic contacts 163 and 165 and semiconductor stripes 151are formed.

A method for forming such a structure will now be described.

Referring to FIG. 20 the exposed portions of the first, second, andthird layers 170 a, 170 b, and 170 c on the areas C are removed toexpose the underlying portions of the extrinsic semiconductor layer 160.

Next, the exposed portions of the extrinsic semiconductor layer 160 andthe underlying portions of the intrinsic semiconductor layer 150 on theareas C as well as the photoresist pattern 54 and 52 are removed by dryetching to expose source and drain (S/D) metals 174 of the areas B.

The photoresist pattern 54 of the channel areas B may be simultaneouslyremoved by etching to remove the extrinsic semiconductor 160 and theintrinsic semiconductor 150, or by a separate etching process. Residualphotoresist of the photoresist pattern 54 in the channel area B may beremoved by ashing. In this step the semiconductor stripes 151 arecompletely formed.

The data conductor layer 170 may be etched by dry etching along with theohmic contact layer 160 and the a-Si layer 150 to simplify manufacturingprocesses. In this case, the three layers 170, 160, and 150 may beetched sequentially in a dry etching chamber, referred to as an“in-situ” method.

Next, as shown in FIG. 21A and FIG. 21B, portions of the S/D metals 174and the underlying portions of the extrinsic semiconductor layer 160 onthe channel areas B are etched to be removed. At this time, the exposedportions of the semiconductor 154 may be etched to have a reducedthickness and the second portion 52 of the photoresist pattern may alsobe partially removed.

Accordingly, the source electrodes 173 and the drain electrodes 175 areseparated from each other, and, the data lines and the ohmic contacts163 and 165 thereunder are completed.

Thereafter, as shown in FIG. 22A and FIG. 22B, a passivation layer 180is formed to cover the data lines 171, the drain electrodes 175, and theexposed portions of the semiconductor stripes 151 that are not coveredwith the data lines 171 and the drain electrodes 175. The passivationlayer 180 preferably comprises a photosensitive organic material thathas good flatness characteristics, a dielectric insulating material thathas a low dielectric constant of under 4.0 such as a-Si:C:O and a-Si:O:Fthat is formed by PECVD or an inorganic material such as silicon nitrideand silicon oxide.

Next, the passivation layer 180 is photo-etched to form a plurality ofcontact holes 185 and 182. When the passivation layer 180 comprises aphotosensitive material, the contact holes 185 and 182 may be formed byphotolithography.

Finally, as previously shown in FIG. 13 and FIG. 14, a plurality ofpixel electrodes 190 and a plurality of contact assistants 82 are formedby sputtering and photo-etching an IZO layer or an ITO layer. The pixelelectrodes 190 and the contact assistants 82 are respectively coupledwith the drain electrodes 175 and an end of the data lines 171 throughthe contact holes 185 and 182.

The present embodiment illustrates gate lines 121 and data lines 171both having a molybdenum-containing layer and an aluminum-containinglayer. However, it is possible that only one of the gate lines 121 anddata lines 171 have multiple layers.

It will be apparent to those skilled in the art that variousmodifications and variation can be made in the present invention withoutdeparting from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A photoresist stripper, comprising: about 5 wt % to about 20 wt %alcohol amine; about 40 wt % to about 70 wt % glycol ether; about 20 wt% to about 40 wt % N-methyl pyrrolidone; and about 0.2 wt % to about 6wt % chelating agent, wherein the chelating agent is one of methylgallate, hydroxyl ethyl piperazine (HEP), and a mixture thereof.
 2. Thephotoresist stripper of claim 1, wherein the alcohol amine is one ofmonoisopropanol amine (CH₃CH(OH)CH₂NH₂), N-monoethanol amine(HO(CH₂)₂NH₂), and a mixture thereof.
 3. The photoresist stripper ofclaim 1, wherein the glycol ether is one of diethylene glycol monoethylether [C₂H₅O(CH₂CH₂O)₂H)], methyl diglycol [CH₃O(CH₂CH₂O)₂H], butyldiglycol [C₄H₉O(CH₂CH₂O)₂H], and a mixture thereof.
 4. The photoresiststripper of claim 1, wherein the alcohol amine is monoisopropanol amine(CH₃CH(OH)CH₂NH₂) and the glycol ether is butyl diglycol[C₄H₉O(CH₂CH₂O)₂H].
 5. The photoresist stripper of claim 1, whereinconcentrations of methyl gallate and hydroxyl ethyl piperazine (HEP) aresubstantially the same.
 6. A photoresist stripper, comprising: about 5wt % to about 20 wt % N-monoethanol amine; about 40 wt % to about 70 wt% butyl diglycol; about 20 wt % to about 40% N-methyl pyrrolidone; andabout 0.2 wt % to about 6 wt % a chelating agent, wherein the chelatingagent is one of methyl gallate, hydroxyl ethyl piperazine (HEP), and amixture thereof.
 7. A photoresist stripper, comprising: about 5 wt % toabout 20 wt % N-monoethanol amine; about 40 wt % to about 70 wt % butyldiglycol; about 20 wt % to about 40 wt % N-methyl pyrrolidone; about 0.1wt % to about 3 wt % methyl gallate; and about 0.1 wt % to about 3 wt %hydroxyl ethyl piperazine.